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  #21  
Old 05-23-2019, 01:18 PM
mckutzy mckutzy is offline
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OK, so with these older briggs flat head engines, does our common thought of valve flutter from clones apply to these motors when the gov is removed??....

And here's some pics from my previous thread....

http://www.diygokarts.com/vb/showthread.php?t=32396

'53 #14


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Old 05-23-2019, 01:26 PM
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Quote:
Originally Posted by mckutzy View Post
OK, so with these older briggs flat head engines, does our common thought of valve flutter from clones apply to these motors when the gov is removed??....

And here's some pics from my previous thread....

http://www.diygokarts.com/vb/showthread.php?t=32396

'52 #14



Yes. At high RPMs. Stock springs are rather weak.
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  #23  
Old 05-23-2019, 01:33 PM
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So one could potentially use this as the protection device as opposed to getting a new con rod??
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Old 05-23-2019, 01:47 PM
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Quote:
Originally Posted by mckutzy View Post
So one could potentially use this as the protection device as opposed to getting a new con rod??
Theoretically...but that’s risky business and I wouldn’t do it unless you just don’t care if your motor lets go. I’ve seen many Briggs with stock springs with blown con rods, usually with disabled governors though. Your motor in the pic is too cool to risk it in my opinion.
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Old 05-23-2019, 02:14 PM
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Yes in this case that kinda was the idea...I was going to go more of the Bronda route as the clone type carb is easier to dial in... and more familiar to me at least...But at the risk of con-rod dissection....

Ya the old beast is quite the thing... definatly dont make things like this anymore... 1" shaft though... So ive been delaying on working with it to another project, dont have a clutch in that size...

---------- Post added at 01:14 PM ---------- Previous post was at 01:10 PM ----------

I guess for the sake of this thread... I can post more pics if anyone wants...
Its now better accessed for me to dig out......
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Old 05-23-2019, 05:28 PM
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Cool briggs dude usually even if the con rod blows the block is fine thats why there are so many briggs that end up parted out sadly
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  #27  
Old 05-24-2019, 09:53 AM
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Quote:
Originally Posted by Budget GoKart View Post
Cool briggs dude usually even if the con rod blows the block is fine thats why there are so many briggs that end up parted out sadly
There's NO guarantees once you remove the governor!!!
I am opposed to flathead governor removal, unless it gets at the minimum, a billet con rod, since I believe flathead rods have just a little more tendency to go around valve float rpms.
I could be wrong.
Hellion and I actually had a PM conversation yesterday discussing cast iron flywheels on these Briggs(which aren't that dangerous unless they're damaged), so I can let a stock flywheel go, but if the rod goes, there's a good chance it'll give you some extra crankcase ventilation.
So no, it's not that rare.
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Old 05-24-2019, 11:44 AM
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1) briggs flatheads have two pins holding the flywheel magnet in place and better casting. They dont blow up unless you go crazy
2) connecting rod will eventually fail if you dont check oil clearance on the crank journal, but its not a huge deal if you keep it relatively stock.
3) i wouldnt go for a honda clone carb, id acutally get on ebay and do a "pz20 carburetor" search and just use the pz20 carb. Might need the main jet drilled a tiny bit, but mine actually ran great straight out of the box and it was only like $13. Just needed to adjust idle mixture.
4) valve float on a flathead (l head wahtever you wanna call it) is not as dangerous as it is on an OHV head. If you hardcore float the valves on ohv you can drop a valve into the combustion chamber and it could completely ruin the head and block. You could bend the valve with piston to valve contact as well. With a flathead, valve float just doesnt have those risks. You dont risk dropping a valve EVER and you dont risk the valve contacting the piston EVER. Sure valve float is bad for other reasons, but you know a good 5500 rpm with a stock engine is okay in my book.

If you do keep the stock rod and it breaks dont come crying baack to us saying we said it was fine haha.

If i was on an extreme budget I would do the following:

1) swap out to a cheap PZ carb with venturi 2-3mm smaller than the intake valve $20
2) make my own intake adapter for the carb $10
3) advance the timing by 4 to 6 degrees and torque back to spec FREE (advance more for methanol)
4) see if i could convert the carb to methanol $5 drill bit set and some sandpaper if needle is too thick
5) port the intake and exhaust. General clean up plus the "inside edges" of the ports get radius-ed pretty good.
6) thread some schedule 40 pipe into the exhaust -$5

send it :-)
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  #29  
Old 05-24-2019, 12:45 PM
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Interesting thanks KF...

On other thoughts as of late upgraded ignition styles .... Older engines use points system, there is transistor replacement in the place of the contacts...
What are some thoughts on this........
Here is a bigger Briggs 23D, similar to the #14 I have above...



Also interesting enough, coming across this as alternative to the same(Im guessing, but thats why the questions) idea but the other way... A powered automotive coil...
Im not too sure if this is more power or just a different style.... equally speaking just to put it out there....
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  #30  
Old 05-24-2019, 08:48 PM
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I've heard enough people on the performance side of building L-heads state that only the exhaust port should be ported/polished and the intake left largely alone...

The intake port benefits from the casting flash that remains inside the port and around the intake valve guide as this induces turbulence and helps atomize the fuel, or so they say.
Apparently B&S Corp knew this was an issue early on since they started adding a sheet metal spiral to the Pulsa-Jet adjustable carburetor in order to do the same thing. But that was for the commercial/residential end user, not racers.


On the other hand, feel free to hog out the exhaust port and round off all the rough edges. The quicker and easier the combustion chamber is evacuated, the better.
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  #31  
Old 05-25-2019, 09:33 AM
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I've got a question about my flathead:
I'm looking for a high flow air filter, and you can't see it on the carb, but there's an air cleaner spacer, with an opening of 1 1/16".
Problem is, most high flow air filters seem to have something like a 1 5/16" carburetor end.
I'm wondering if there's somewhere I could get an air cleaner of the right size, or get/make and adapter.
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  #32  
Old 05-25-2019, 11:22 AM
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A plate of aluminum or the like with the hole to fit on the bottom will do... depending on the filter.....
There are a whole host of air filters out there... Im sure there is something out there...
K&N has a custom selection of filters.....

Heck with a little thought, a GX390 big block clone type filter could be fitted....
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  #33  
Old 05-26-2019, 01:12 PM
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Just looked at a high flow K&N, which would be K&N E-4142, and I can't find them for much less than $50!!!
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  #34  
Old 05-26-2019, 01:21 PM
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Then...Make your own to fit the filter you have or can get cheaply...
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  #35  
Old 05-26-2019, 01:28 PM
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For the filter there’s all types and most “high flow” filters have rubber tube that connects it to the carb, so even if it’s nit exact, either bigger or smaller the rubber gives you wiggle room, and use a hose clamp, do some searching
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Old 05-26-2019, 01:35 PM
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First thing I'm going to do is see if it'll still run ok with the stock air filter. Because I know with the rain hood and prefilter and everything will be a lot more restrictive than just the main air filter cartridge.
Besides. it's not like on clone engines, where the air has to go through the rain hood, through the filter, down the airbox, 'round a 90 degree angle, and then into the carb.
With the way it's configured, there's not really any parts I can eliminate easily.
We'll see.
The main reason I'm worried about increasing performance is because I plan to do some casual racing with some other people I know, but just today I found out:
Two of them are homemade, one with terrible welds(i.e he pressed the brakes and the spindles broke off and kept going)
The other one is a racing kart, but it's got a stock Predator 212(I'm pretty sure), and it's been sitting outside in the backyard for months in the Texas weather.
I'm not too worried, I might be able to beat them.
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  #37  
Old 05-26-2019, 08:13 PM
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If you aren't doing too many burnouts that is
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  #38  
Old 06-19-2019, 04:52 PM
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I have 2 briggs 5hp flat heads that I'm wanting to get running they are both orange montgomery ward, one off of a tiller and one off of a snow blower. My question is what carb would be good to get rid of the gas tank top thing that's on them?
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  #39  
Old 06-19-2019, 05:11 PM
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Check the PTO end (end of crankshaft) to see if they are suitable for what you want to use them for...... go kart or mini bike?

The carb-on-gas-tank setup is basically without fault and heck, kart racers raced with a modified Pulsa-Jet that was bored out and used bigger jets.

Otherwise, you can use just about any carburetor as long as you have a compatible intake manifold, but then you gotta mount a fuel tank somewhere else.



The beauty of the gas tank mounted Pulsa Jet is that it has its own fuel pump which is constantly feeding fuel to the carb, feverishly pumping that fuel, and there's no float bowl to drain and go empty (as with a normal carburetor), as if you were climbing a long steep hill.
As long as that gas tank is full enough, the pickup tube on the carb will the keep the fuel flowing to the engine...
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Old 06-19-2019, 06:20 PM
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ok thanks, the shafts are both straight one is model number 130212 and one is 130207. I was told the on tank carb is junk and I think they are ugly so may switch it out
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